Multi-layered films are useful in forming hermetic seals, protecting packaged food products from loss of flavor, staleness, or spoilage due to light, oxygen and moisture. In addition, multi-layered films prevent undesirable leaching of the product to the outside of the film. For example, oily food products have the potential for some oil to leach out of the package.
Films formed of biopolymer layers generally are not effective as a barrier against oxygen or moisture. That is, such barriers allow oxygen and moisture to pass (i.e., allow diffusion). One approach to solving this problem has been to apply a metallization layer to the biopolymer layer. However, such biopolymer/metallization combinations do not improve the barrier qualities to sufficient levels. Such combination layers act as a partial barrier to oxygen and moisture but still allow some moisture and oxygen vapors to pass.
For the foregoing reasons, it is desirable to have a high barrier film that solves the above problems.